The Airgraph was an Eastman-Kodak invention that helped to move large volumes of mail efficiently during WWII. Americans may know it as "V" mail - a means to communicate with military located in far-away places.
This was a solution to a logistics weight and volume problem. There was a limited amount of weight and volume capacity on aircraft. Mail, a high priority item, competed for availability. Letters were microfilmed. The film was sent by air to a depot destination, enlarged and printed, then sent in special envelopes to the recipient. Figures are quoted that 1700 single page letters could be put on a 100 foot roll of 16 mm film weighing about 5 ounces. Those same letters would have weighed about 35 pounds and take about 1.5 cubic feet, about the same size and weight as 5 gallons of fuel. Duplicate copies of the films were made to insure the mail would not be lost in case of the loss of the aircraft. These copies were destroyed once the letters were printed at the destination.
The British military started using this system in 1941 between London and Cairo. Special form were used requesting the writer to use large block letters since the finished product would be about half sized (4x5 inches).
Since there were many Irish nationals serving in the British military, the system was expanded to include Irish addresses in 1943. In Ireland, using a special form, a writer would address the letter by filling the top "TO" block, and then writing the letter in the marked box. If an additional page was needed, a separate form would be sent as a separate letter. The completed form was mailed to Dublin where it was cancelled and censored by Irish censors. The forms were then sent to London for British censorship. The forms were then microfilmed and the completed film sent by air to the processing center nearest to the destination where it was printed and placed in special envelopes for delivery. The overseas sender followed the same process.
Processing centers for airgraphs were located in the London area, Cairo, Bombay, Nairobi, Johannesburg, Melbourne, Wellington, and Toronto. Later Algiers, Naples, Columbo, and Calcutta were added.
This was a popular form for people to use. It is estimated over 350 million airgraphs were used in the four year life span. Several different form varieties were used.
Irish Aerogrammes and Airgraphs, William J. Murphy, Eire Philatelic Assn, 1997. This book is available from the EPA Publications Manager.